Geologic & Sinkhole Risk • 6 min read • Last Updated November 1, 2026

Sinkhole Risk Map by Address: How to Check Karst Bedrock & Ground Subsidence Before Closing

Compiled & Verified by: FullPropertyReport Environmental & Market Research Team

Primary Sources: U.S. EPA ECHO/RCRA/SDWIS • FEMA NFHL/NRI • USDA SSURGO • FHFA HPI • HUD SAFMR • U.S. Census

Buying in Florida, Tennessee, Pennsylvania, Missouri, Kentucky, Texas, or Virginia? Learn how carbonate limestone and dolostone karst geology creates sinkhole hazards and how to screen any address.

What Is Karst Topography and Why Does It Cause Sinkholes?

Roughly 20% of the United States is underlain by soluble rock formations such as limestone, dolomite, gypsum, and halite—known geologically as karst terrain. Over time, slightly acidic rainwater and fluctuating groundwater tables dissolve subsurface cavities in the bedrock. When the overlying soil arch collapses into a void, a cover-collapse or cover-subsidence sinkhole forms.

Why Karst Bedrock Also Amplifies Groundwater & Radon Risk

Because karst limestone contains open fissures and underground solution conduits rather than natural sand filtration, surface spills from leaking underground fuel tanks or agricultural runoff can travel rapidly into private wells. Karst fractures also serve as high-permeability pathways for indoor soil-gas radon migration.

Frequently Asked Questions

Which states have the highest karst sinkhole risk?

The highest concentrations of evaporite and carbonate karst sinkholes occur in Florida, Tennessee, Kentucky, Missouri, Alabama, Pennsylvania, Virginia, West Virginia, Texas, and Indiana.

Does standard homeowners insurance cover sinkhole collapse?

Most standard HO-3 homeowners insurance policies exclude earth movement and gradual soil subsidence unless you purchase a specific Sinkhole Loss Coverage endorsement or catastrophic ground cover collapse rider.